We are applying for funds to support the purchase of instrumentation necessary to serve the needs of the Tufts Flow Cytometry Core. This Core Facility provides the only cell sorting capability for the entire extended Tufts research community covering the Tufts University Medical, Dental, Veterinary and Engineering Schools as well as the Tufts-New England Medical Center and St Elizabeth's Hospital. Currently this includes 47 biomedical research laboratories that actively use cell sorting of which 31 are NIH funded. These include investigators working in a broad range of health and disease related areas including immunology, cancer, microbiology, disease pathogenesis and tissue engineering. The facility has been run for the last 15 years by Mr. Allen Parmelee, a skilled and highly respected operator, under the direct supervision of the P.I. and the Core Advisory Committee. Under their direction the facility has grown, become highly successful and maintained financial stability through competitive pricing and Departmental support. 90% of facility time is dedicated to the NIH funded work of the Major User Group. We are now asking for an Influx cell sorter with 5 lasers (BD Biosciences). Our current cell sorters (12 and 13 year old MoFlos) are outdated, prone to breaking down and only one has 5 laser, 4-way sorting capability. We expect these ageing machines to become increasingly unreliable and by 2013, at the latest, our machines will no longer be supported for parts. Consequently our current sorting capability will soon be lost. Guaranteed continuity of the cell sorting service therefore requires the addition of a new machine in 2013 that at least matches the capabilities of our current configuration. Not only will a new Influx cell sorter provide increased reliability, it also possesses major technical advantages over our existing MoFlo. These include a dramatic increase in the number of detectors and 5 independent pinholes. This instrument will effectively replace our 5 laser MoFlo while providing access to a range of techniques not currently available to us such as the use of certain dye and fluorescent protein configurations that operate at high Stokes shifts (e.g., certai transfer dyes and FRET systems). The cost efficiency and high standards of our facility have ensured steady use of the cell sorters which will increase as the core becomes folded into University wide plans to develop large scale, multiple investigator, research collaborations supported by state of the art facilities and cores.